1. Field of the Invention
This invention relates to a sprocket wheel of an endless track-type-vehicle, more particularly to a sprocket wheel which can absorb or reduce noise and shock at or above a preselected magnitude caused, for example, by running on a ragged ground.
2. Description of the Prior Art
During travel of an endless-track-type vehicle on a ragged ground, drive and/or driven sprocket wheels of the endless track-type vehicle are often subjected to severe impacts from other elements which are used to drive or be driven by the wheels. These repeated severe impacts sometimes generate damaging forces, undesirable wear rate, and noise which result in wastes of endless-track bushings, backward speed reduction gears, bearings, etc. The wastes of these elements tend to be expedited in proportion to an increase of weight of the vehicle.
In order to eliminate the above disadvantages, some measures have been proposed as shown in U.S. Pat. Nos. 4,022,072 4,069,856 and 4,080,008 so far as the applicant knows. However, the prior art disclosed in these patents is not sufficient to completely deal with the aforesaid disadvantages.